Radiometric Dating: How Rocks Can Look Older Than They Are

CEH ^ | 04/82015

[SeekAndFind]

Researchers find that the most common dating method can produce “spuriously old” dates.

A team from Europe took a closer look at how uranium-lead ages are determined, and found problems. One of the assumptions going into dating zircons (zirconium silicate crystals encasing uranium that decays to lead) is that the clock is “reset” when the parent rock under goes the high heat and pressure of metamorphism. This team found that nanosphere inclusions of extraneous metallic lead (Pb) can confuse the dating technique, making the rock look older than it is. Writing in PNAS, they say:

Zircon (ZrSiO₄) is the most commonly used geochronometer, preserving age and geochemical information through a wide range of geological processes. However, zircon U–Pb geochronology can be affected by redistribution of radiogenic Pb, which is incompatible in the crystal structure. This phenomenon is particularly common in zircon that has experienced ultra-high temperature metamorphism, where ion imaging has revealed submicrometer domains that are sufficiently heterogeneously distributed to severely perturb ages, in some cases yielding apparent Hadean (>4 Ga) ages from younger zircons.

The paper provides what they feel are safeguards to prevent erroneous dates. It appears, however, that this finding overthrows common assumptions used in the dating technique.

The reliability of the oldest zircon ages, which include some reversely discordant analyses (i.e., with U–Pb ages older than ²⁰⁷Pb/²⁰⁶Pb ages), has been questioned based on evidence from ion imaging for disturbance of the U–Pb system. This is important because ²⁰⁷Pb/²⁰⁶Pb ages are generally considered to be more robust than U–Pb ages for older zircons. However, if radiogenic Pb has been decoupled from its parent U and not locally incorporated into the crystal lattice during an ancient geological event, when radiogenic ²⁰⁷Pb/²⁰⁶Pb values are significantly higher than at present, reverse discordance and spuriously old ²⁰⁷Pb/²⁰⁶Pb age estimates may result.

In other words, the more lead in the crystal (“decoupled from its parent U”), the more a scientist might infer that it is billions of years old, when some of that lead got mixed in when a younger rock underwent metamorphism.

In the ICR publication Acts & Facts, Dr. Vernon R. Cupps has been publishing a detailed analysis of how results can be corrupted in radiometric dating. He has shown numerous ways that deceptively old dates can be produced, depending on the assumptions used. The mathematical techniques are sound, but like with computer programs, wrong assumptions can make for garbage-in, garbage-out conclusions. Those interested may wish to study this new PNAS paper to see how often this problem occurs in practice.

[Resettozero]

Radiometric dating is less fruitful than Internet dating.

[lee martell]

How long before Hillary’s name and image are mentioned in connection with weathered old rocks or dubious vintage?
Oh! I just did both.

[PapaBear3625]

The problem for Creationists is that it doesn't matter if a dating method is off by 10% or even 50%. Anything which shows the Earth as having been created much earlier than 4,000 BC throws the creation timeline out the window.

If something is really 100 million years old, instead of 200 million years old, it still invalidates the Creation timeline.

[Verginius Rufus]

This also can apply to people. Helen Thomas wasn’t really as old as she looked.

[Verginius Rufus]

There was a thread earlier today about NGC 2903, a beautiful spiral galaxy in Leo, which is believed to be 20 million light-years distant. That is, what we are seeing is how it looked 20 million years ago when the light from that galaxy started traveling our way.

Are we supposed to believe that that is an illusion, that NGC 2903 is much closer, or that it was there 20 million years ago, but that the earth didn't come into being until 4004 B.C.?

[tjd1454]

If something is really 100 million years old, instead of 200 million years old, it still invalidates the Creation timeline.

One could just as easily argue that any methodology that has been found to be off by 100% is unreliable.

Suppose that the rocks were found to be only 1 million years old, would you use the same argument, viz, that therefore the Creation timeline is wrong - even though the methodology used to discredit it was found to be off by 19,900%?

All dating techniques other than Carbon 14 which can be historically validated necessarily employ built-in assumptions which - in this case - have already been shown to be wildly inaccurate.

[the_daug]

Decay of the speed of light?

[Still Thinking]

Even C14 dating, the principle of which is valid, is accurate only to the degree that the percentage of C14 vs total carbon has been constant or nearly so over epochal periods of time. Not an unreasonable assumption, but hardly unquestionable. A water canopy cutting the amount of ionizing solar radiation reaching the surface of the earth might render the starting percentage much lower, thus implying much older remains when tested. Plus, the Bible never says to interpret creative “days” as literal solar earth days, so my understanding of the Bible is not that it says the universe sprang into being abruptly in 4000 BCE. The Bible uses the word “day” with many interpretations as we do today. (see, there’s a contemporary non-literal use right there!)

[tjd1454]

Are we supposed to believe that that is an illusion, that NGC 2903 is much closer, or that it was there 20 million years ago, but that the earth didn't come into being until 4004 B.C.?

Are we supposed to believe that the universe "somehow" came into existence without any outside Agency, and that the unimaginable complexity of life managed to come into existence solely as a result of time + chance + matter?

Are we expected to believe that the obvious impossibility of such a proposition is answered simply by injecting huge amounts of time into the process, as if that obviated the self-evident truth that infinite complexity cannot spontaneously arise out of nothing?

As the teleological argument for the existence of God argues, a design requires a Designer. Or, as the argument for Contingency - which Bishop Coppleston argued with such effect against the atheist Bertrand Russell - states, everything that exists demands a sufficient cause. So the question is: what is the sufficient Cause for the vastness of the universe and the virtually infinite level of complexity found in living things?

Supposing I was walking in the woods and came across an old wristwatch lying on the path. If I began waxing eloquently about the amazing conjunction of just the right minerals in the ground with the injection of energy in the form of lightning strikes, produced the watch, my sanity would be rightly questioned, for everyone knows that anything that show evidence of purposeful design did not come into existence through purely natural forces. And everything from the common housefly to the human body shows an infinite greater level of complexity.

[tacticalogic]

Suppose that the rocks were found to be only 1 million years old

If they are only 1 million years old, then virtually all of the samples are contaminated with non-radiogenic lead sufficient to alter their apparent age by hundreds of orders of magnitude.

[Larry Lucido]

I had an uncle who was older than dirt.

Therefore, all dirt is younger than my uncle.

[Sherman Logan]

Sorry, only the Young Earth Creationists are affected as you say. Not all Creationists are of that particular sect.

[Agamemnon]

If something is really 100 million years old, instead of 200 million years old, it still invalidates the Creation timeline.

Actually, the larger problem is for evolutionists who every day are discovering a far more complex universe than an evolutionary dogma can account for with only the alleged 4.5 billion year time frame they have boxed themselves into long ago.

So now radiometric dating that you have relied on so compulsively actually now cuts the amount of time you think you have to account for some very extraordinary things which are already statistically impossible by factors of hundreds to have occurred by chance at all.

No, the conundrum is all evolutionists

If you don't have the time you don't have the premise. Trouble is you are losing evidence of any time by your own measures you thought you had (and desperately needed to somehow make it all work).

The impossibility of evolution becomes only that much more illogical an explanation for anything and those who rely on it only look that much more silly for continuing to hold on to it.

FReegards!

[Spirochete]

Radiometric dating of Earth's rocks has always yielded inconsistent results because they have been weathered by varying degrees and reworked by plate tectonics.

Samples of the Canyon Diablo meteorites were chosen in 1953 because they have been subjected to relatively little melting or weathering. Researchers were fairly certain that this particular meteor was a member of the primordial solar nebula and chose samples of it for radiometric dating. This is the origin of the 4.5 billion year figure; the early to mid 1950s.

http://en.wikipedia.org/wiki/Age_of_the_Earth#Canyon_Diablo_meteorite

[muir_redwoods]

..."everything that exists demands a sufficient cause."

If you assert that, then I must accept you believe that. Therefore, what is the sufficient cause of God?

[SeekAndFind]

RE: Researchers were fairly certain that this particular meteor was a member of the primordial solar nebula and chose samples of it for radiometric dating.

OK, here are a few questions:

1) The first major assumption built into radiometric dating is the idea that the parent elements have decayed in the past A THE EXACT SAME RATE as they are decaying today. no one alive today knows what kind of environment existed in the distant past. How do we know how fast elements decayed in the past?

Suppose you come upon a man who is cutting down trees in a forest. You watch him for an entire hour, and he cuts down only 1 tree. Then you count the number of trees he has cut—31 in all. If you assume that he has been cutting trees down at the same rate, then you calculate that he has chopped for 31 hours. However, when you talk to the man, he tells you that, earlier in the day when his ax was sharp and his stomach was full, he was cutting down 5 trees an hour; only in the last hour had he slacked off. With this information, you now understand that he worked for only seven hours, not 31. How do we prove the assumption that the decay rates in the past were the same as they are now?

2) The second assumption is this — We must assume that the daughter element in the sample was not there in the beginning. must assume that the daughter element in the sample was not there in the beginning.

Suppose you go to a swimming pool and find a hose that is pumping water into the pool at a rate of 100 gallons an hour. You discover that the pool has 3,000 gallons of water in it. You calculate that the hose must have been running for 30 hours. However, when you ask the owner of the pool how long she has been running the hose, she tells you that she has been running it for only 1 hour. Most of the water was already in the pool due to a heavy rain the night before. If you assumed that all the water came from the hose, your calculations would be way off—29 hours off to be exact.

I am not saying that these assumptions are wrong in respect to Canyon Diablo meteorites chosen in 1953, but how do you prove that?

[SeekAndFind]

EDIT TO ADD:

Another problem is that the different radiometric methods drastically DISAGREE with one another at times.

On occasion, the same sample of rock can be dated by the different methods, and the dates can differ by several hundred million years.

Some rocks from Hawaii for example, that were known to have formed about two hundred years ago rendered a date of 160 million to 3 billion years when dated by the potassium-argon method.

Another time, the same basalt rock in Nigeria was given a date of 95 million years when dated by the potassium-argon method, and 750 million years when dated by the uranium-helium method.

That is why it is appropriate to QUESTION THEIR BUILT-IN ASSUMPTIONS.

[Spirochete]

I am not saying that these assumptions are wrong in respect to Canyon Diablo meteorites chosen in 1953, but how do you prove that?

You're right about the assumptions. Also, one has to make assumptions about the original concentration of radioisotope being measured, and its original ratio to the decay products.

I can't really prove anything. I was trying to establish the relatively recent origin of the 4.55 Gyr figure.

Figures as from 40 million to 8 billion years has been measured from lunar rock samples, so it's nowhere near an exact science. Hundreds of measurements are taken to see where the trend is.

This might interest you: http://www.scienceagainstevolution.org/v12i9f.htm

[tjd1454]

Gotcha! Is that what you thought? Did you really think you had posed the ultimate unanswerable objection to the existence of God?

I unfortunately don’t have time to try to go through all the responses to this old canard. Plus, I’m not a philosopher - here’s a site for starters that does an adequate job. There are probably a hundred others:

http://www.godandscience.org/apologetics/who_created_god.html